???????? ??????????????????NUMBER????Scale??????????????????????????????????????????????????и?TEST?????и?????????NUMBER??????????????????? CREATE TABLE TEST (      Category VARCHAR(12)??      QTY  NUM
??????????????????????NUMBER????Scale?????????????????????????????????????????????????и?TEST?????и?????????NUMBER???????????????????
CREATE TABLE TEST
(
Category VARCHAR(12)??
QTY  NUMBER
)
INSERT INTO TEST
SELECT 'M'?? 12 FROM DUAL UNION ALL
SELECT 'C'?? 0.99999999999999999 FROM DUAL;
COMMIT;
??????????????TEST??????QTY?????1??

???????????SQL?????????SUM_QTY??????1

??????????????α???????????????????????QTY??????????.99999999999999999
DECLARE  CURSOR c_test
IS
SELECT Category?? SUM(QTY) AS SUM_QTY FROM TEST
GROUP BY Category;
c_row c_test%rowtype;
begin
for c_row in c_test loop
dbms_output.put_line('the result is ' || c_row.SUM_QTY);
end loop;
end;
the result is .99999999999999999
the result is 12
????????????????????????? ?????????????????????????????????????????????0.999999999. ?????????????????????????????????????????????????????????????NUMBER???????NUMBER (p?? s) ????????????? p(precision)??????s(scale)???С????????????????????????38??scale??????Χ?-84??127?? Number(p) ??????????????????Number(p?? 0)?? ????????p??s??NUMBER?????????????????38?? ????scale??0. ?????????SELECT????У??????.99999999999999999 ??????1?????????α??У???????????????ε?????????о??????????????????????????????????o??????????÷??????????????????? ???￡????÷????????飬????????
????????????????????(p)????(s)??????1???
????·  ????????????????????? > p-s ???Oracle????
????·  ?????????С?????????? > s ???Oracle??????
????·  ??s(scale)????????Oracle??С????????s?????????????
????·  ??s > p ??? p???С??????sλ?????????ж???λ????????????p??Oracle?????С?????sλ??????????????